Motor-driven press and actuating means therefor

ABSTRACT

A motor-driven hydraulic fabricating press having a reciprocating ram slidably mounted in a press frame and actuated by means of rotary actuators. One or more drive shafts are journaled in the frame, each drive shaft driven by at least one rotary hydraulic actuator, and are coupled to the reciprocating ram by means converting rotary motion into linear motion. Where a plurality of drive shafts is utilized, the drive shafts are coupled to each other by means of a kinematic crank chain.

United States Patent [191 Goff [ Mar. 19, 1974- MOTOR-DRIVEN PRESS AND ACTUATlNG MEANS THEREFOR Inventor: Otis Ward Goff, 7151 Carlsbrook,

Portage, Mich. 49081 Filed: May 10, 1972 Appl. No.: 252,099

US. Cl 100/232, 72/450, 100/269 R, lOO/282, lOO/292, 425/406 Int. Cl. B30b 7/04 Field of Search 425/406; 72/450, 452; 100/292, 282, 269 R. 232

References Cited UNITED STATES PATENTS 5/1953 Pater .j. 100/292 x 9/1953 Wilkins 100/282 1/1955 Trirnble 72/415 Primary Drummer-Billy J. Wilhite Attorney, Agent, or Firm-Gordo:n W. Hueschen [57] ABSTRACT A motor-driven hydraulic fabricating press having a reciprocating ram slidably mounted in a press frame and actuated by means of rotary actuators. One or more drive shafts are journaled in the frame, each drive shaft driven by at least one rotary hydraulic actuator, and are coupled to the reciprocating ram by means converting rotary motion into linear motion. Where a plurality of drive shafts is utilized. the drive shafts are coupled to each other by means of a kinematic crank chain.

6 Claims, 9 Drawing Figures BACKGROUND OF THE INVENTION The present invention relates to a hydraulic press for fabricating metal or plastic parts.

Conventionally, hydraulic presses for blanking, forming, trimming, piercing, or the like operations employ pistons to actuate the press ram. However, especially where relatively large rams are employed it is difficult if not impossible to achieve a uniform distribution of force across the ram platen, and in many instances undesirable distortion of the ram platen is experienced.

It is an object of the present invention to provide a motor-driven hydraulic fabricating press having an improved alignment of the press ram relative to the press bed.

Another object of the present invention is to reduce the weight carried by the frame of a fabricating press.

It is a further object to provide a motor-driven hydraulic fabricatingpress where a plurality of pressure points is provided for driving the press ram.

Yet another object is to provide a hydraulic fabricating press where the press ram is driven by means of a plurality of drive shafts, each drive shaft providing more than one pressure point for the press ram and the drive shafts being coupled together with a kinematic crank chain. l

Still other objects of this invention will readily presentth emselves to one skilled in the art upon reference to the ensuingspecification,the accompanying drawings, and the claims. l l

SUMMARY or THE INVENTION manner hereinabove set forth, and a kinematic crank chain coupling connects at least two of the drive shafts.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings,

FIG. 1 is-a front elevational view of the press of this invention, partially broken away to show interior detail;

FIG. 2 is a side elevational view of the press of this invention; 7 E

FIG. 3 is a sectional elevation of the press taken along line III III in FIG. 1; v

. FIG. 4 is a sectional plan view of a lower portion of the press taken along line IV IV in FIG. 1;

FIG. 5 is a sectional. view showing a typical vertical die assembly and lateral die assembly for the press of this invention; I

FIG. 6 is a front elevational view showing a press of this invention provided with a plurality of drive shafts;

FIG. 7 is an elevational view of one end of the press shown in FIG. 6 and showing'a kinematic crank chain;

FIG. 8 is a fragmentary elevational view of the other end of the press shown in FIG. 6;. and

FIG. 9 is a sectional elevation of the press taken along line IX IX in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, press 10 is provided with a press frame comprising upright frame members 11 and 12 held in a spaced relationship relative to each other by tie bars 13, 1 4, 15 and 16. Press. bed 17 is mounted within the frame and is reinforced by bed crowns 18 and 19 as well as by auxiliary bed crown members such as auxiliary members 20 and 21 (FIGS. 2 and 3).

Reciprocating. vertical ram 22 comprises upper platen 23 suspended by means of clevis brackets 24 and 25 and pitman arms 26and 27 from shaft 28 which is journaled in upright frame members 11 and 12. Vertical ram 22 is actuated by means of a full eccentric integrally mounted on the shaft and suitably coupled to ram 22. To this end, circular pitnam 29 is journaled in pitman arm 27 and is eccentrically fixed to shaft 28 by means of key 30 so that the rotational plane of pitman 29 is substantially normal to the longitudinal axis of shaft 28. A similar pitman is journaled in pitman arm 26 and is secured to shaft 28 in the same manner. Pit

man arm 27 is pivotally connected to clevis bracket 25 r cal ram 22 from drive shaft 28. Rotary hydraulic actuator 85 is connected to shaft 28 and imparts rotary motion thereto which is translated into linear motion for vertical ram 22 by the circularpitmans such aspitman 29 and pitman arms 26 and 27. Alternatively, in order to obtain the required throw the drive shaft can be a crankshaft having a plurality of connecting rods journaled on the crankshaft and pivotally connected to the vertical ram. a

Upper platen 23 is provided with yokes 34 and 35 at opposite ends thereof which slidably engage guideways 32 and 33 and guideways 36 and .37, respectively. Upper platen 23 is reinforced against deflection by ram crowns 83 and 84 mounted on the upper surface thereof.

Rotating stop 38 is affixed to shaft 28 by meansof key 39. Stop 38 abuts against stop pin 40 at the end of the upward stroke of vertical ram 22 and abuts against stop pin 41 at the end of the closing, i.e., downward strokeof vertical ram 22. i

' Inorder to provide multiple motion operation, lateral ram 42 can be slidably mounted between upright frame members 11 end 12 in lateral rarn guideways 43 and 44 and adapted for lateral motion substantially parallel to press bed 17. Lateral ram 42 comprises lateral punch holder 45 reinforced against deflection by crown 46, and connecting rods 47 and 48 which terminate in clevis brackets 49 and 50, respectively, pivotally attached to respective pitman arms 51 and 52 by means of wrist pins such as pin 53 for pitman arm 52 (FIGS.

2, 3 and 4). Preferably clevis brackets 49 and are tached by means of wrist pins to respective pitman arms 60 and 61. Again it is readily apparent that a plurality of pressure points is provided for each ram from drive shaft 63.

Lateral linear motion is imparted to lateral ram 42 by rotary hydraulic actuator 62 coupled to shaft 63 suit ably journaled in bearings 64, 65, 66 and 67. A pitman, such as 68 journaled in pitman arm 52 and eccentrically fixed on shaft 63 by means of key 69 so that the rotational plane of pitman 68 is substantially normal to the longitudinal axis of shaft 63, is provided for each of pitman arms 51, 52, 60 and 61 and translates rotary motion of shaft 63 into linear motion by lateral ram 42. as well as into linear motion by optional lateral ram 54. If desired, additional lateral rams can be provided superposed over lateral rams 42 and 54 and actuated by the same fluid motor means, i.e., by rotary hydraulic actuator 62. Also, additional lateral rams can be provided on the remaining free sides of press bed 17, actuated by a separate fluid motor means.

The forward and return travel of lateral rams 42 and 54 is determined by rotating stop 70 provided with contact bar 71 which abuts stop block 72 (FIG. 1) or stop block 73 (FIG. 4) depending on whether lateral rams 42 and 54 are retracted or extended.

A typical die assembly arrangement fo the multiple motion press using actuating means of this invention is shown in FIG. 5. Die shoe 74 is suitably mounted on press bed 17 in any convenient manner and lower vertical die element 75 together with backup member 76, if necessary, fitted therein. Upper vertical die elements 77 and 78 are mounted on vertical ram. 22 by fitting these elements in or on upper platen 23, together with spring pad 79, if needed or desirable. Sheet metal workpiece 80, when placed in the resulting vertical die assembly between lower vertical die element 75 and upper vertical die elements 77 and 78 will be subjected to a first forming operation upon a downward stroke of vertical ram 22. At the completion of the closing or downward stroke vertical ram 22 is held in dwell position with workpiece 80 clamped within the vertical die assembly which assembly is at such time in a position to function as a lateral die element in a subsequent forming operation. For this purpose a desired die cavity such as cavity 81 is provided in lower vertical die element 75 adapted to cooperate with lateral die element 82 fitted in lateral punch holder 45 of lateral ram 42. Alternatively a die cavity for cooperation with a lateral die element'such as element 82 can be provided in appropriate circumstances in one of the upper vertical die elements; however, usually'this is undesirable because the lateral die element can be readily damaged by the inadvertent raising of vertical ram 22 before lateral ram 42 is retracted in such instances. Also, if desired, the relative positions of the upper and lower dieelements in'the vertical die assembly can be reversed.

1 Where a plurality of lateral rams is employed in the forming operations, indexing means for a die element or elements in the vertical die assembly canbe provided in any convenient manner to shift these elements inwardly after the forming operations have been completed in order to facilitate the removal of the shaped workpiece and then subsequently to return the shifted elements to their normal position prior to the commencement of the next forming cycle. In some operations such as blanking or trimming, a lateral ram is not necessary and can be dispensed with. I

The method of sheet metal fabrication contemplated by the present invention involves the steps of providing a sheet metal blank, either as a separate piece of from coil or sheet stock, subjecting said blank to a first forming operation by the action of cooperating vertical die elements, retaining said blank after the first forming operation clamped between said vertical die elements, and subjecting the retained blank to a subsequent forming operation by the action of a movable lateral die element which cooperates with a lateral surface of one of the cooperating vertical die elements to effect the subsequent forming operation. The blank can be formed separately, or it can be produced by the vertical ram itself during the operating cycle. As is readily apparent from the detailed discussion of this invention set forth hereinabove, either the upper vertical die element or the lower vertical die element can be the die element which cooperates with the movable lateral die element to provide the necessary lateral die assembly.

By a suitable selection of die elements the present press can also be used in die casting applications for molding, trimming and similar operations, as well as in the fabrication of plastics, for example, in vacuum form molding, trimming of a injection molded plastic parts, etc.

The multiple motion press of this invention can be operated manually or it can be programmed for'automatic operation during the forming cycle or cycles. In a manual operation, a workpiece is appropriately positioned in the machine and the closing stroke of vertical reciprocating ram 22 inititated by supplying hydraulic fluid from a suitable source under pressure to rotary hydraulic actuator 85. At the completion of the closing stroke by vertical ram 22 the first forming operation has been effected and vertical ram 22 is held in dwell position clamping the now partially formed workpiece in the vertical die assembly Thereafter, lateral movement of lateral ram 42 is started by supplying hydraulic fluid to rotary hydraulic actuator 62 and continued until lateral die element 82 engages the workpiece and shapes or trims the same in cooperation with the lateral die cavity provided in the vertical die assembly. Lateral ram 42 is then retracted by reversing the rotational direction of actuator 62, vertical ram 22 raised to its uppermost position by reversing the rotational direction of actuator 85, and the fabricated workpiece removed from the press in any convenient manner.

In'automatic operation the same sequence of operational steps is followed except that the relative positions of vertical ram 22 and lateral ram 42 are sensed by appropriately placed limit switches or similar sensors and a subsequent operation initiated when machine movement completing a'preceding operational step trips a limit switch which then initiates the next operational step. For instance, proper positioning of a sheet metal blank in the press can trip a first limit switch which opens a first valve permitting hydraulic fluid under pressure to flow to rotary hydraulic actuator 85 thereby initiating and continuing the downward stroke of vertical ram 22. As the closing strok is completed, ram 22 trips a second limit switch which opens a second valve permitting hydraulic fluid under pressure to flow to rotary hydraulic actuator 62 thereby initiating and continuing the lateral movement or stroke of lateral ram 42 singly or together with optional lateral ram 54. During this time period the first valve remains open and vertical ram 22 continues to bear against the a valve reversing the flow of hydraulic fluid to actuator 85 and thus causing vertical ram 22 to be raised to its original upper position, and as ram 22 reaches its original position a fifth limit switch is tripped which resets the valves for the next forming cycle.

Another embodiment of this invention, operable in the same manner asset forth hereinabove, is shown in FIGS. 6 through 9. This particular embodiment offers the advantage of a plurality of coplanar yet non-linear pressure points for the reciprocating ram, thereby substantially improving force distribution across the ram platen and minimizing the misalignment thereof relative to the press bed when under load. In addition, by coupling parallel drive shafts by means of a kinematic crank chain the output of rotary hydraulic actuators coupled to the drive shafts is uniformly distributed to all connected drive shafts. Thus, even if a rotary hydraulic actuator coupled to a particular drive shaft fails in service, the force distribution across the ram platen will remain substantially uniform. Also, this particular embodiment of the present invention permits the selective use of less than all rotary hydraulic actuators during the major portion of a ram stroke with all available rotary hydraulic actuators being put into service, through appropriate valving in the hydraulic system, only near and at the bottom of the closingstroke so as to exert the desired high tonnage.

Referring to FIG. 6, press 130 .is provided with a press frame comprising upright frame members 86 and 87 held in a spaced relationship relative to each other by tie bars 88, 89, 90 and 91 (FIGS..6 and 9). Press bed 92 is mounted within the frame and is reinforced by bed crowns 93 and 94.

Reciprocating ram 95 is suspended by means of clevis brackets such as brackets 96, 97 and 98 and pitman arms 99, 100 and 101 from substantially parallel drive shafts 102 and 103 which are suitably journaled in frame members 86 and 87. Circular pitmans such as 104 and 105 are journaled in respective pitman arms 100 and 101 and are eccentrically fixed to shafts 102 and 103 by keys 106 and 107, respectively, so that the rotationalplanes of pitmans 104 and 105 are substantially normal to the longitudinal axes of shafts 102 and 103. A similar pitman is journaled in pitman arm 99 and secured to shaft 103 in like manner. A corresponding assembly is also provided on shaft 103 at the end thereof opposite that where circular pitman 105 is affixed. The pitmans are pivotally connected to their respective clevis brackets by means of wrist pins such as pins 131 and 132 shown for pitmans 100 and 101. In this manner a total of four pressure points are provided for ram 95, two from shaft 102 andtwo from shaft 103. More pressure points can be provided by mounting additional pitmans and pitman arm assemblies on shafts 102 and 103 in the manner hereinabove set forth.

Rotary motion is imparted to shafts 102 and 103 by rotary hydraulic actuators 109 and 110 FIGS. 6 and 7) and is translated into linear motion for ram 95 by the circular pitmans and the respective pitman arms. While only one rotary hydraulic actuator is shown for each drive shaft, if desired, a rotary hydraulic actuator can be-coupled to each end of a given. drive shaft. Also, instead of the eccentric provided on drive shafts 103 and 103 by circular pitmans such as 104 and 105, drive shafts 102 and 103 can be crankshafts provided with connecting rods journaled thereon and pivotally connected to ram 95, e.g., by means of a wrist pin, ball and socket, or the like. Platen 111 of ram is provided with yokes 112 (FIG. 7) and 113 (FIG. 9) at opposite ends thereof which slidably engage guidways 114 and 115 and guideways 116 and 117, respectively. Further stiffness for platen 111 is provided by ram crown 108 mounted thereon between shafts 102 and 103.

In order to assure a uniform force distribution on platen 111 during operation or in the event actuator output is not uniform, shafts 102 and 103 are coupled by means of a kinematic crank chain. Preferably shafts 102 and 103 are coupled at both ends by kinematic crank chains 118 and 119. Crank chain 118 comprises cranks 120 and 121 fixedly mounted on shafts 102 and 103 by means of keys 122 and 123, respectively.

Cranks 120 and 121, in turn, are joined by connecting rod or link 124 pivotally connected to cranks 120 and 121 at the free ends thereof.

As can be seen from FIG. 8, crank chain 119 is similar to crank chain 118 and comprises crank 125 fixedly mounted on shaft 103 by means of key 126, crank 127 fixedly mounted on shaft 102 by means of key 128, and connecting rod or link 129 pivotally connected to cranks 125 and 127 at the free ends thereof. Crank chains 118 and 119 are preferably parallel to each other but out of phase relative to each other, preferably by about 90 degrees, so as to facilitate the movement thereof and to avoid binding of one of the crank chains if at a dwell position of ram 95 either crank chain hap-. pens to have both cranks and the connecting rod aligned along the, same line.

In the foregoing specification the terms upper, lower and vertical have been used in setting forth the various interacting elements of the press of this inventionn with reference to the conventional position of the press in the interest of clarity. It will be apparent to one skilled in the art, however, that the press of this invention can be operated as well in a tilted position or when turned on one side if it is expedient to do so from the standpoint of transporting workpieces to and/or away from the press.

Similarly, in some of the specific: embodiments illustrated hereinabove, a lateral ram is shown positioned substantially normal to a' vertical ram. However, the relative anglebetween the rams can vary, if desired, from an acute angle to an obtuse angle, depending on the workpiece that is to be fabricated.

The foregoing specification and the drawings are intended as illustrative and are not to be construed as limiting. Still other variations and rearrangements of parts within the spirit and scope of this invention are possible as is apparent to the skilled artisan.

.1. A motor-driven hydraulic fabricating press which comprises a press frame; v i

a plurality of substantially parallel drive shafts journaled in said frame;

a rotary hydraulic actuator coupled to each of said drive shafts for imparting rotary motion thereto;

a reciprocating ram means slidably mounted on said frame; I i

means converting rotary motion into linear motion operably connecting each drive shaft with said reciprocating ram; and

a kinematic crank chain coupling at least two of Said drive shafts. v 2. The motor-driven hydraulic fabricating press in accordance with claim 1 wherein said means converting rotary motion into linear motion comprise a plurality of pitman arms pivotally connected to said reciprocating ram means; a circular pitman journaled in each of said pitman arms; and at least a pair of said circular pitmans eccentrically fixed on each of said drive shafts in a spaced relationship relative to each other and so that the rotational plane of each of said pitmans is substantially normal to the longitudinal axis of said drive shafts. 3. The motor-driven hydraulic fabricating press in accordance with claim 1 wherein said drive shafts are coupled by kinematic crank chains situated at both ends of said drive shafts, said crank chains being parallel to each other but out of phase relative to each other.

4. The motor-driven hydraulic fabricating press in accordance with claim 3 wherein said crank chains are about out of phase relative to each other.

5. The motor-driven hydraulic fabricating press in accordance with claim 1 wherein said kinematic crank chain comprises a crank member rigidly affixed to each with said lateral reciprocating ram means. 

1. A motor-driven hydraulic fabricating press which comprises a press frame; a plurality of substantially parallel drive shafts journaled in said frame; a rotary hydraulic actuator coupled to each of said drive shafts for imparting rotary motion thereto; a reciprocating ram means slidably mounted on said frame; means converting rotary motion into linear motion operably connecting each drive shaft with said reciprocating ram; and a kinematic crank chain coupling at least two of said drive shafts.
 2. The motor-driven hydraulic fabricating press in accordance with claim 1 wherein said means converting rotary motion into linear motion comprise a plurality of pitman arms pivotally connected to said reciprocating ram means; a circular pitman journaled in each of said pitman arms; and at least a pair of said circular pitmans eccentrically fixed on each of said drive shafts in a spaced relationship relative to each other and so that the rotational plane of each of said pitmans is substantially normal to the longitudinal axis of said drive shafts.
 3. The motor-driven hydraulic fabricating press in accordance with claim 1 wherein said drive shafts are coupled by kinematic crank chains situated at both ends of said drive shafts, said crank chains being parallel to each other but out of phase relative to each other.
 4. The motor-driven hydraulic fabricating press in accordance with claim 3 wherein said crank chains are about 90* out of phase relative to each other.
 5. The motor-driven hydraulic fabricating press in accordance with claim 1 wherein said kinematic crank chain comprises a crank member rigidly affixed to each of said drive shafts and a connecting rod pivotally connected to at least two of said crank members affixed to said drive shafts.
 6. A motor-driven hydraulic fabricating press in accordance with claim 1, additionally being provided with at least one reciprocating lateral ram means slidably mounted on said frame; an additional drive shaft journaled in said frame; an additional hydraulic rotary actuator coupled to said shaft for imparting rotary motion thereto; and means converting rotary motion into linear motion operably connecting said additional shaft with said lateral reciprocating ram means. 